The IACV is a digital linear actuator (DLA) that accurately controls throttle airflow in an engine system. The need for using an IACV is that vehicle pollution emission control regulations require more precise air/fuel ratios and thus cleaner tailpipe emissions. The conventional IACV is an automotive grade can-stack style stepper motor which has been in production for 10-15 years.
The vehicle environment for which the IACV is used can be extreme from the cold temperatures of the arctic, to hot dusty deserts, to rain soaked jungles. Under normal vehicle driving conditions, the automotive intake manifold air filtration system is sufficient to protect the IACV from contamination. In the extreme vehicle applications, the IACV can be exposed to the following contamination: dust, moisture, fuel, EGR hot gas, carburetor cleaners, etc. The presence of contaminates in the IACV can lead to reduced component life and subsequent customer complaints or warranty returns.
The conventional IACV configuration has open ball bearings which are at risk to jamming or seizing due to contaminates, particularly in Asian environments. Asian motors can have “dirty” intake manifolds as compared to the NAFTA and European engines. The NAFTA-Euro engines are much cleaner in the sense of fuel vapor and wet exhaust gas recirculation are better designed or controlled within the intake manifold.
Thus, there is a need to provide an improved bearing of an IACV that is not prone to seize in harsh environments.